Diatomy

Diatomy is the study of diatoms, a diverse group of aquatic microalgae within the phylum Bacillariophyta. Diatoms are characterized by their frustules, rigid cell walls made of hydrated silica that are often highly ornamented with species-specific patterns. The term diatomy appears in some texts as the science of diatoms, though modern literature more commonly uses diatom biology, taxonomy, or ecology.

Most diatoms are unicellular, though some form colonies. They are divided into two major groups: centric diatoms, which have circular or radially symmetrical frustules, and pennate diatoms, which are elongated or boat-shaped. The frustule comprises two halves that fit together like a box and lid, with pores and ridges that influence nutrient exchange and light capture. Diatoms reproduce primarily by asexual division, which gradually reduces cell size; sexual reproduction occurs to restore a larger, typical cell size via zygote formation or auxospores. They are photoautotrophs requiring light and dissolved silicate for growth.

Ecologically, diatoms are major primary producers in oceans and freshwater systems, contributing substantially to global photosynthesis and forming the base of many aquatic food webs. They also play a crucial role in the silicon cycle, as their silica shells contribute to sediment formation when they die and sink to the seafloor. Their fossilized remains provide a rich microfossil record used in biostratigraphy and paleoenvironmental studies.

Humans exploit diatoms in several ways, notably through diatomaceous earth, which is used for filtration, abrasion, and insulation. Diatom shells also find applications in nanotechnology and materials science as sources of biosilica. Research methods include light and electron microscopy, culturing, and molecular analysis to resolve taxonomy and evolutionary relationships.